NASA scientists have created a new recipe that captures key flavors of the brownish-orange atmosphere around Saturn’s largest moon, Titan.
The recipe is used for lab experiments designed to simulate Titan’s chemistry. With this approach, the team was able to classify a previously unidentified material discovered by NASA’s Cassini spacecraft in the moon’s smoggy haze.
“Now we can say that this material has a strong aromatic character, which helps us understand more about the complex mixture of molecules that makes up Titan’s haze,” said Melissa Trainer, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
The material had been detected earlier in data gathered by Cassini’s Composite Infrared Spectrometer, an instrument that makes observations at wavelengths in the far infrared region, beyond red light. The spectral signature of the material suggested it was made up of a mixture of molecules.
To investigate that mixture, the researchers turned to the tried-and-true approach of combining gases in a chamber and letting them react. The idea is that if the experiment starts with the right gases and under the right conditions, the reactions in the lab should yield the same products found in Titan’s smoggy atmosphere. The process is like being given a slice of cake and trying to figure out the recipe by tasting it. If you can make a cake that tastes like the original slice, then you chose the right ingredients.
The challenge is that the possibilities are almost limitless in this case. Titan’s dirty orange color comes from a mixture of hydrocarbons (molecules that contain hydrogen and carbon) and nitrogen-carrying chemicals called nitriles. The family of hydrocarbons already has hundreds of thousands of members, identified from plants and fossil fuels on Earth, and more could exist.
The logical starting point was to begin with the two gases most plentiful in Titan’s atmosphere: nitrogen and methane. But these experiments never produced a mixture with a spectral signature to match to the one seen by Cassini; neither have similar experiments conducted by other groups.
Promising results finally came when the researchers added a third gas, essentially tweaking the flavors in the recipe for the first time. The team began with benzene, which has been identified in Titan’s atmosphere, followed by a series of closely related chemicals that are likely to be present there. All of these gases belong to the subfamily of hydrocarbons known as aromatics.
The outcome was best results were obtained when the scientists chose an aromatic that contained nitrogen. When team members analyzed those lab products, they detected spectral features that matched up well with the distinctive signature that had been extracted from the Titan data by Carrie Anderson, a Cassini participating scientist at Goddard and a co-author on this study.
“This is the closest anyone has come, to our knowledge, to recreating with lab experiments this particular feature seen in the Cassini data,” said Joshua Sebree, the lead author of the study, available online in Icarus. Sebree is a former postdoctoral fellow at Goddard who is now an assistant professor at the University of Northern Iowa in Cedar Falls.
Now that the basic recipe has been demonstrated, future work will concentrate on tweaking the experimental conditions to perfect it.
“Titan’s chemical makeup is veritable zoo of complex molecules,” said Scott Edgington, Cassini Deputy Project Scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California. “With the combination of laboratory experiments and Cassini data, we gain an understanding of just how complex and wondrous this Earth-like moon really is.”
The laboratory experiments were funded by NASA’s Planetary Atmospheres program. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the mission for NASA’s Science Mission Directorate in Washington. Goddard built and manages the Composite Infrared Spectrometer.
Liz Zubritsky | Eurek Alert!
Space radiation won't stop NASA's human exploration
18.10.2017 | NASA/Johnson Space Center
Study shows how water could have flowed on 'cold and icy' ancient Mars
18.10.2017 | Brown University
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
18.10.2017 | Materials Sciences
18.10.2017 | Physics and Astronomy
18.10.2017 | Physics and Astronomy